Why do some things glow under a UV/black light?

What do scorpions and teeth have in common? They both glow under a UV/black light! If you think about it, we see these types of lights quite often, in amusement parks, Halloween, bowling alleys, and even pest control. The real question is why do some things glow under UV/black lights, while others don’t?

A black light is actually a type of UV light, there are many types of UV or Ultraviolet lights, but the one in a black light is specifically UV-A. Ultraviolet light is a type of light with a less than normal wavelength, meaning it is out of the the visibility spectrum. UV lights are the the same type of light that emits from the sun. When these UV lights hit and reflect off of certain things, interesting reactions will happen. For example, when UV rays from the sun hit your skin you could get sunburned. In the case of a black light, when the UV light hits the chemical element phosphorus, it reacts by glowing. “Coincidentally”, phosphorus is common in plasma screen televisions, certain fabrics, teeth, fingernails, and scorpions! So if you’re ever at a bowling alley and your shirt, teeth, and fingernails start to glow, the answer is phosphorus!